Peroxide treatment of fatty oils



Patented Mar. 11, 1952 UNITED STATES PATENT OFFICE.

No-Drawingr Application September 26, 1950, SerialNo. 186,926

8Qlaims, (o1. zoo-405.6)

This nve tion relat s t a m th d or imnmw ns the dry n pr per ies:qfz s urat d: i t y ils. of, marine, vegetable; and animal origin, as well; as; to, the new and, improved products obtainable thereby, which products are particularly adapted. for. se inathepaint. la q er a n h. and. linoleum industries. Morehpa fiticularly, the invention: pertains: totreatment of.- unsaturated fatt oils with. a peroxide con a nin a t ar alkyl peroxy radical whereby a product having excellent drying propertiesisobtained.

Drying oilssuch as linseed oil have long been used in the manufacture of; paints, varnishes, inks, etc. Suehoils as linseed oil have been considered quite satisfactory for such purposes although considerable room forimprovement has been recognized withv regards to ability of films of the oil to dry hard. Other oils, such as fish oil and soy bean. oil haye been quiteunsatisfac; tory-because the, oil will not dry to a hardfilm, but instead the: film tends toremainsticky or tacky.

It, has now been discovered thatneve produets havingexcellent dryingw properties are, obtained by heating a fatty oil haying an iodine value above 120 at about 100 to 250} in the. presence of; a peroxide containing a tertiary-alkyd peroxy radicaL. Not only does the treatment convert such. oils as fishoil and soy bean oilinto products which dry to'hard filmsf-reeiof tack Q S ickiness, but also, the treatment enables oils like linseed oil to be converted toproducts which dry to hard films.

The action of the peroxide containing a tertiary-alkyl" peroxy radical in the process of the invention appears to be; unique. Thus, while it has previously been proposed to heat fatty oils with various peroxides, particularly benzoyl peroxide, for the purpose of bleaching the oil, treatment with such peroxides does not give products having the outstanding drying properties of the oils oi the present invention. The unique char. acter' of the action of the peroxides containing a tertiary-alkyl peroxy radical will be evident from; the comparative results following.

Alkali-refined winterized sardine oil having an iodine value of 198 grams iodine per 100' grams of; oil (determined by the Woburn method described by von Mikusch and Frazier, Ind. Chem Anal. Ed, vol. 13, pages 782 9 (1941)) was emiployed for the tests in which the action or die. tertiaryebutyl peroxide was compared with, that of benzoyl peroxide and curnene hydroperoxide (2-phen 1- r r v r ne T rdine oil had been winterized to stand clear for 2 to 3. hours minimum at 32 F. The respectiye perox ides in the amount stated in 'Ifable I below were a de to he -t in co ta n rs h ch ere then immersed in a thermostatically controlledhfiat' g; a In or r o d e h b nza l eroxide n the 11 i h u r enea ina it. w s a ded aso u onni c i sw isht f nzene. Asl

str am arbon. d x esa was e sedthrq eh e. oi mi s to. n q d en e a it t on a d xel deairt The o l r sscn ainine t ee xi e were un ea e .5 0-111 one hour m i t i e a h t mperat r fe anxed nel 5. hours. For comparison, an oil sample coniaini s n n i ewa s arl he ted. A er e in i cobal t t (c b -e h 1hex ete) as drier n mo 00% Cobalt asad e to, he. treated oils and to an; untreated oil sample, The Oils were en sp ead on glas at s h t aidof a 2 mil doctor blade and subjectedto drying tests in a constant temperature-room maintained. at 7-7 F. and relative humidity; The r n properties of. t i s are ivenin'l able The, drying tests were conducted according to the, procedures described by Henry- A. Gardner in Physical and Chemical Examinationof Raints, varnishes, Lacquers and; Colors," 1939, pages 106-:107.

TABLE, 1

I Diz'lertiary-Butyl Peroxide A de Ber-oxide Bentoyl Peroxide Cumene Hydro:

Peroxide 2.75 2.25hrs lessthan 3 day re i ss s 2.25mi 1 5 than 3 days les than3 days,

untreated oil or oil given heat treatment without peroxide.

The method of the invention is applicable to treatment of a wide variety of fatty oils. New products with marked improvement in drying properties are obtained by subjecting fatty oils having iodine values of at least 120 to the method.

Among representative examplesof drying oils improved by the method are such oils as sardine (pilchard), menhaden, whale, soy bean, hempseed, linseed, perilla, safilower, oiticica;'walnut, tung and dehydrated castor. Althoughthe oils maybe used in raw condition, itis preferred that they first be subjected to one or more of the usual refining procedures such as so-called alkali-refining. Moreover, it is preferred that the fish oils be winterized in order that fractions containing stearin and the like be removed from the oil. It is preferred that the fish oil be winterized so as to stand clear for 2 to 3 hours at 32 F. If desired, mixtures of two or more different oils containing at least 5% of each may be treated;

I In execution of the method, the mixture of oil and peroxide containing a tertiary-alkyl peroxide radical is heated at about 100 C. to 250 C. Depending somewhat upon the particular oil treated,

the heating iscontinued for about 1 to 20 hours. Excellent results are obtained at temperatures of about 150 C. to 200 C. in 6 to 10 hours heating, and therefore, temperatures in thisrange are preferred with a temperature in the neighborhood of 175 C. being particularly suitable. The heating is-discontinued prior to gellation of the oil since the treatment with the peroxide is not primarily a polymerization. In fact, the average molecular weight of the products having the new drying properties is usually not more than about 30% greater than that of the original oil although in some cases it may be desirable to continue the heatinguntil the molecular weight has increased 50% or even doubled. Treated oil with molecular 1 weight twice as great as that of the original oil is still far below the gellation point.'

The heating may be conducted with the reaction mixture under ordinary atmospheric pressure, but when a temperature above the boiling point ofthe peroxide employed is used, it is desirable to utilize superatmospheric pressure sufficiently high that appreciable loss of the peroxide by boiling does not occur.

It appears that by far the best results and products are obtained by treatment with di-tertiarythe peroxide and its amount, and the temperature,

-- slightly higher. This indicates that bodying is d butyl perphthalate, 2,2-bis-(tertiary-butyl peroxy) propane, 2,2-bis- (tertiary-butyl peroxy) butane, l-(tertiary-butyl peroxy) ethanol, and the like. In general, it is preferred to employ peroxides rather than hydroperoxides-i. e., compounds containing the tertiary-alkyl peroxy radical linked to another carbon atom. Single compounds are usually employed, but if desired, mixtures of two or more may be utilizede. g., ditertiary-butyl peroxide in admixture with tertiary-butyl hydroperoxide.

Various proportions of peroxide to oil are used in the invention. In general, about 0.5% to 10% of peroxide is added to the oil. Very good results are obtained with use of about an added 2% to 6% of peroxide. In executing the process, the total amount of the peroxide may be added to the oil and the mixture heated to effect the treatment. It has been found, however, that more efficient use of the treating agent is obtained by adding the peroxide portion-wise or continuously during the period of maintaining the oil at'treatment temperature. In this procedure, the oil is usually heated to or about to the desired treatment temperature andthe peroxide, as a concentrated solution of about 10% to concentration in the same oil as treated, is added over a period of time while maintaining the temperature at the desired point. The heating may be continued for such time as desired after completion of the addition of the peroxide.

The action of the tertiary-alkyl peroxide on the oil whereby excellent drying properties are imparted thereto is not fully understood. Such peroxides are known to be polymerization catalysts for olefinically unsaturated compounds. However, the heat treatment with the peroxide does not cause substantial polymerization of the oil. Although the viscosity of the treated oil is con-- siderably increased, the molecular weight is only not a major factor in improvement of drying properties of the oil. Furthermore, there is only small decrease in iodine value of the treated oil. Examination of the ultraviolet absorption specl trum indicates that the peroxide treatment results butyl peroxide. If desired, however, any peroxide containing a tertiary-alkyl peroxy radical may be used such as, for example, di-tertiary amyl peroxide, d'i-tertiary-octyl peroxide, monochloro-ditertiary-butyl peroxide, symmetrical dichloro-ditertiary-butyl peroxide, asymmetrical dichlorodi-tertiary-butyl peroxide, ,monobromo-di-tertiary-a'myl' peroxide, tertiary-butyl tertiary-amyl peroxide, isopropyl tertiary-butyl peroxide, ethyl tertiary-amyl peroxide, tertiary-butyl hydroperoxide, tertiary-hexyl hydroperoxide, m'ono'chlorotertiary-butyl hydroperoxide, tertiary-butyl per- ,in considerable conjugation as compared to the raw oil or oil heat-bodied in the absence of the peroxide. Moreover, the infra-red spectrum of the peroxide-treated oil and that of untreated oils demonstrates the presence of an increased amount of alpha-type olefinic groups (CH2=CH) as well as transtype unsaturation. It therefore appears that the peroxide treatment causes considerable isomerization of new type on the oils. Several specific embodiments of the invention are given in the following examples, but it is to 0 be understood that the invention is not limited to details therein. I

- Example I A mixture of 5% di-tertiary-butyl peroxide and 95% of alkali-refined winterized sardine oil was heated for 5 hours at 175 C. which caused the at 32 F.

For purposes of comparison and in'order to have a heat bodied'pr'oduct having approximately the same viscosity as the peroxide-treated oil, a sample of raw oil was heated up to 300 C. in 80 minutes and maintained at this temperature for with a 2 mil doctorblade. The films were dried at 77 F. and 50%. relative humidity. The results follow.

' TABLE II" T Peroxide- Heat- Treated Untreated Bodied Viscosity; Gardner-Helm"-.. Iodine value, Wijs. Molecular weight. Refractive index, 1m Drying Time:

Set to touch 1 hour"... 4 hours... 5.5 hours. Dust free 1.5 hours.. 5.5 hours-. more: than 7 hours. Tack frec 2i1ours... 6.5 hours. mat in 50 wins. Hard 4hours.. not in 50 hours. Cotton. free 6.5 hours Example II A series of treatments at different temperatures were effected on alkali-refined winterized sardine oil while continuously adding di-tertiarybutyl peroxide. The oil was placed in a glass reaction vessel equipped with a stirrer anddropping funnel. The vessel was immersed in a thermostatically controlled bath and a very slow stream of nitrogen was bubbled through the charge. The oil was heated to treatment temperature in about 50 minutesand then the peroxide as a solution of 15 parts by weight in 100 parts of oil was added dropwise from the dropping funnel. After all the peroxide had been added, heating was continued for about minutes additional time. the treatment along with results of drying tests of films containing 0.05% cobalt as cobalt octoate prepared using a 2 mil doctor blade and dried at 77 F. and relative humidity.

TABLE III Table III gives details of 40 TABLE Untreated Treated Oil Oil Viscosity, Gardner-Heidi; A G'-H. Relractiveiindexmsnl i 1.4750, 1.4703. Drying time, hours:

Set to toucln. 6.25.. 4.25. Dust free 8 Taclcireo... Harddry...

TABLE V Peroxide- Heat-Bodied Oil Treated Oil Refractive index, no 1.4810 1.4821. Molecular weight 810 1100. Viscosity, Garclner-Holdt A-Al. C. Iodine value, Wijs... 183 173. Drying time, hours:

Set to touch 2.7-... 2.5. Dust free 3.2 2.7. Hard dry Not in 30 days... 7 days.

I claim as my invention:

1. A process of improving the drying properties of fatty oil having an iodine value of at least 120 which comprises heating said oil at about 100 C. to 250 C. in the presence of a peroxide compound containing a tertiary-alkyl peroxy radical.

Per cent Peroxide Temperature, C...

Time, hours Refractive Index not. Molecular Weight H--. Viscosity, Gardner-Holdt Iodine value, Woburn Drying time, hours:

Set to touch Dust free. Tack free. Hard less than 72..- not in lodays.

Example III Alkali-refined winterized sardine oil was Example IV Alkali-refined soy bean oil was treated as described in Example II at 175" C. for 6 hours with 5.6% di-tertiary-butyl peroxide. The results including drying tests effected as described hereinbefore follow.

Drying tests conducted as described 2. A process of improving the drying properties of a fatty oil having an iodine value of at least 120 which comprises heating said oil at about 150 C. to 200 C. in the presence of about an added 0.5% to 10% by weight of a peroxide compound containing a tertiary-alkyl peroxy radical linked directly to another carbon atom than is present in said tertiary-alkyl group.

3. A process of improving the drying properties of a fatty oil having an iodine value above 120 which comprises heating said oil at about C. to 250 C. in the presence of di-tertiarybutyl peroxide.

4. A process of improving the drying properties of a fatty oil of natural origin having an iodine value of at least which comprises heating said oil at a temperature of about 100 C. to

250 C. while adding thereto about 0.5% to 10% by weight of a peroxide containing a tertiaryalkyl peroxy radical.

5. A process of improving the drying properties of sardine oil which comprises heating said oil at about 100 C. to 250 C. in the presence of 0.5% to 10% by weight of a peroxide containing a tertiary-alkyl peroxy radical.

6. A process of improving the drying properties of sardine oil which comprises heating said oil at about 150 C. to 200 C. in admixture with about an added 0.5% to 10% by weight of ditertiary-butyl peroxide.

7. A process of improving'the drying properties of soy bean oil which comprises heating said oil at about 150' C. to 200 Crin the di-tertiary-butyl peroxide.

8. A process of improving the drying properties of linseed oil which comprises heating said oil at about 150 C. to 200 C. in the presence of di-tertiary-butyl peroxide.

7 LEONARD P. W'IEBE.

REFERENCES CITED UNITED STATES PATENTS Name Date Bradley Oct. 29, 1940 presence of Number 

1. A PROCESS OF IMPROVING THE DRYING PROPERTIES OF FATTY OIL HAVING AN IODINE VALUE OF AT LEAST 120 WHICH COMPRISES HEATING SAID OIL AT ABOUT 100* C. TO 250* C. IN THE PRESENCE OF A PEROXIDE COMPOUND CONTAINING A TERTIARY-ALKYL PEROXY RADICAL. 